Indicating and controlling system



July 21; 1936. D TAYLOR 2,048,653

INDICATI NG AND CONTROLLING SYSTEM Filed Dec. 19, 1954 I 3mm Daniel G. Taylor Patented July 21, 1 936 PATENT OFFICE INDICATING AND CONTROLLING SYSTEM Daniel G. Taylor, Minneapolis, Minm, assignor to Minneapolis-Honeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application December 19,1934. Serial No. 758,244

16 Claims. (Cl. 236-1) This invention relates to indicating and controlling-systems in general and more particularly to liqu d level indicating and controlling systems for use in a heating system employing a heater, a liquid fuel burner and a liquid fuel reservoir therefor. d

It is an object of this invention to provide an indicating and controlling system for a heating system having a liquid fuel burner and reservoir therefor wherein a visual indication is made when the liquid level in the reservoir lowers to a predetermined value.

Another object is to provide a control system i for use with a heating system of the class described wherein the normal operation of the fuel burner is stopped when the liquid level in the reservoir lowers to a predetermined value.

A further object is to provide a heating system having a liquid fuel burner and a liquid fuel reservoir therefor which is controlled by a space thermostat wherein a visual indication is made at the space thermostat and wherein the setting of the thermostat is effectively lowered when the liquid level in the reservoir lowers to a predetermined value.

A still further object is to provide an indicating and controlling system for a heating system having a liquid fuel burner, a liquid fuel reservoir therefor and a space thermostat for controlling the operation of the liquid fuel burner wherein the setting of the thermostat is effectively lowered upon the establishment of a predetermined low liquid level in the fuel reservoir whereby the temperature of the space to be heated is lowered to give a sensation of coldness to indicate that the fuel supply inthe reservoir is low.

Other objects and advantages will become apparent to those skilled in the art by reference to the accompanying specification, claims and draw-- and described as applied to a hot water heating system having a hot water boiler ill with a pipe i I leading upwardly from the top thereof to a hot water header I2. Risers l3 extend upwardly from the hot water header l2 to radiators IE to supply hot water thereto. the radiators I5 is controlled by the usual manually operated valves l4 located in the risers l3.

Cold water is taken from the radiators I5 through risers I6, cold water return header I1 and. pipe I8 to the lower portion of boiler In to again be heated therein,

Water in the boiler I0 is heated by a conventional electrically driven liquid fuel burner 20. Located on the liquid fuel burner is a control box 2| for controlling the operation thereof having the usual safety switches and control mechanism contained therein. The expended gases are carried from the "combustion chamber of the boiler I!) through a flue 22 to a chimney, not shown.

Located below the level of the liquid fuel burner 20 is a liquid fuel reservoir 25, liquid fuel 26 being supplied to the reservoir by some means, not shown. Extending upwardly from a point adjacent the bottom of the liquid fuel reservoir is a vertical-pipe 27 which connects to a supply pipe 28'. 7

Upon operation of the electrically driven liquid fuel burner 20, liquid fuel 26 is drawn upwardly from the reservoir 25 to the electrically driven liquid fuel burner 20. The liquid fuel burner 20 and the vertical pipe 2'! are provided with the such location is shown in Fig. 2 at 25'. The

liquid fuel reservoir 25 may be connected to the supply pipe 28 by means of a pipe shown in dotted lines at 21'.

Located in the room or space to be heated is a The supply of hot water to' space thermostat 30 which may be of the type.

close-:2 position. By means of an adjusting screw 34, the tension in the spring 33 maybe adjusted to determine at which temperature'the mercury switch 3| will be closed all of which is pointed out in the above referred to pa ant.

Wires 31 and 38 are connected to some source of power, not shown, wire 31 extending to one of v the electrodes of mercury switch 3| and wire 38 extending to the control box 3| of the liquid fuel burner 26. A wire 39 connects the other electrode of mercury switch 3| to the control box 2| of the liquid fuel burner 26.

- When the room or space temperature falls to a predetermined value, mercury switch 3| of the space thermostat 36 will be tilted to a closed po- 'sition to complete an electric circuit from the source of power, not shown, through wire 31,

'mercury switch 3|, wire 36, control box 2!, and

wire 38 to operate the liquid fuel burner 26. Operation of the liquid fuel burner 26 causes a vacuum to be created in the supply pipe 26 and the vertical pipe 21 to draw liquid fuel 26 therethrough into the liquid fuel burner 26 whereby combustion is established in the boiler l6 to provide heat to the space or room to be heated by means of the radiator 16. When the space or room temperature has risen to a predeterminedvalue, mercuryswitch 3| will be tilted to an open position, breaking the above mentioned circuit and stopping operation of the liquid fuel burner 26 until the space thermostat 36 again .calls for heat.

If the reservoir 26' of Fig. 2 is used instead of reservoir 25, the general operation will be the same except that fuel will be fed to the liquid fuel burner 26 under pressure caused by the hydraulic head of the liquid fuel and not under vacuum as above described.

Connected to the pipe 28 by means of a pipe ll is a combined indicating and switching mechanism 46 which may be of the Bourdon tube type .which is responsive to either pressure or vacuum existing in the pipe 28. This type of instrument is old in the art and a specific description thereof is not considered necessary, it being sumcient to state that the Bourdon tube contained therein operates a combined pointer and contact 62. Located adjacent the combined pointer and contact '62 is an adjustable contact 63, having a handle 44 extending outwardlyfrom the instrument 66 -whereby propereadjustment of the adjustable contact 63 may be made. Located on the face of indicator and switching mechanism l6.

the instrument 46 are graduations in terms of pressure and vacuum, in this instance the vacuum graduations being located at the left of the zero point and the pressure graduations beinglocated at the right of the zero point.

When no pressure or vacuum exists in the pipe 28, the combined pointer and contact 62 is main-- tained at its center or zero position. when a vacuum occurs in the pipe 23, the pointer moves to the left in .an amount proportionate to the amount of vacuum tablished in the pipe 28. Upon the existence 0 a pressure in the pipe 28,

the pointer 42 moves to theright a proportionateamount with respect-to the amount of pressure in the pipe 26. y

A step'down transformer is generally indicated at 66 and has a primary'6l which-may be connected bymeans of wires 63 and 64 to wires 36 and 36. One end of the secondary 62 of the supplied to the transformer 66, and when the movable pointer and contact 42 engages the adjustable contact 43, the warning lamp 61 is lighted. If it be desirable to use a warning light of line voltage, the transformer 66 should be 6.

eliminated and the indicator l6 and the warning.

light should be'directly connected in parallel to the liquid fuel burner 26. I

When the level of the liquid 26 in the reservoir 26 is high, a certain vacuum is requiredtojdraw l0 the liquid 26 into the liquid fuel burner '26 and this amount of vacuum is reflected in the instrument 46. When the level of liquid 26 in the reservoir 26 is low, a greater vacuum is required to draw the liquid 26 into the liquid fuel burner 20.

This difference in vacuum is due to the change in the liquid head of the liquid 26 in the reservoir 26. The various degrees of vacuum required. to draw the liquid 26 from the reservoir are directly reflected by a proportionate movement of the movable pointer and contact 62 of themessure instrument 6. By properly adjusting the movable contact 63, an electric circuit may be completed through the adjustable contact 63 and the movable contact 42 upon the establishment of v a predetermined low liquid level in the reservoir 25. The graduations 46 form a convenient means for determining the amount of adjustment of the adjustable contact 43. Upon the establishment of such low liquid level and the consequent engagement of contacts 62 and 63, an electric cir-, 'cuit is completed from secondary 62 of trans-, former 66, through wire 66, contacts 43 and 62, wire 56, warning lamp 61 and wire 68, back to the secondary 62. Since, in the preferred einbodiment of this invention wires-63 and are connected respectively to wires 38 and 38. the transformer 66 is connected in parallel with the. liquid fuel burner 26 and it will not becomeenergized untilthe liquid fuel burner 26 is placed 40 in operation. When the liquid level in the reservoir 26 reaches a predetermined minimum and when the room thermostat 36 calls for heat to operate the liquid fuel burner 26, the warning light 51 will be lighted to notify the users of the heating system that the liquid fuel supply in the reservoir is extremely low.

The warning light 61 has another function be-: sides that of merely visually indicating as described above. When the light 61 is lighted, heat -56 is given off thereby which effects the volatile fill in the bellows 32 to expand the bellows 32.to tend to maintain the mercury switch 3! towards open position. Because of this, a greater decrease in the space temperature acting on the bel1ows132 to contract the same is required to move the mercury switch 3! towards closed position. Therefore, the liquid fuelburner 26 cannot be maintained in operation under normal temperature conditions when thewarning light is lighted. It 430 will only be maintained in operation at temperatures lower than those for which the space thermostat 36 is set. Due to the fact that the warning light 61 lowers the effective setting of the space thermostat 36, the room temperature will 65 be maintained at a lower temperature than normal. Such a condition will give a sensation of coldness to the occupants of the space to be heated to sensually notify them that the liquid fuel supply in the reservoir 26 is extremely low. 76

By reason of this, a double indicator is in effect I provided for giving visual indication of the supply of liquid fuel'and also a sensual indication of the coldness.

The operation of the device is the same as above when the reservoir 25' is used'except that the changes in liquid level inthe reservoir 25' will be reflected as positive pressure changes instead predetermined low pressure caused by the drop in hydraulic head inthe reservoir 25'.

In the above description of the preferred form of this invention, it is noted thatthe warning light 51 may only be lighted when the liquid fuel burner 20 is in operation because the step down transformer 50 is connected in parallel with the liquid fuel burner 20. If it be desired to maintain the warning light 51 lighted at all times when the liquid level in the reservoir 25 or 25' reaches a predetermined low value, regardless of whether the liquid fuel burner 20 is in operation, the primary of the step down transformer 50 may be connected directly to the source of power. Such connection may be accomplished by means of -wiresi3' and 54' shown in Fig. 3 to be connected respectively to wires 31 and 38.

From the above, it is seen that I have provided an indicating system for use with a liquid fuel heating system wherein visual and sensual indications are given to the users thereof upon the establishment of a low liquid level in the liquid fuel reservoir.

While several embodiments of this invention have been shown and described, it is obvious that many modifications may be apparent to those skilled in the art and consequently this invention is to be limited only by the scope of the appended v claims and the prior art.

I claim as my invention:

1. The combination with a heating system having a heater for heating a space, a liquid burner and a liquid reservoir therefor, of a space thermostat for controlling the operation of the liquid burner, control means responsive to changes in liquid level in said reservoir and means connected to said control means for lowering the setting of said space thermostat upon the establishment of a predetermined low liquid level in said reservoir.

In combination with a heating system having a heater for heating a space, a liquid burner and a liquid storage reservoir therefor, of a space thermostat for starting the operation of said liquid burner upon the lowering of the space temperature to a predetermined value, and means responsive to a predetermined low liquid level in said liquid storage reservoir, to-prevent operation of said liquid burner when the space temperature lowers to said predetermined value.

3. The combination with a heating system having a heater for heating a space, a liquid burner and a liquid reservoir therefor, of a space thermostat for starting the operation of said liquid burner upon the lowering of the space temperature to a'predetermined value, control means responsive to changes in liquid level in said reservoir, and means connected to said control means for affecting the operation of said space thermostat upon the establishment of a predetermined low liquid level in said reservoir requiring a space temperature lower than said predetermined value to start said liquid burner.

4. In a heating system of the class described having .a heater for heating a space, a liquid trolling the operation of said liquid burner,,a 5

warning light associated with 'said space thermostat, and means responsive to the level of the liquid in said storage reservoir to light said warn-- ing light and stop operation of said liquid burner. 5. In a heating system of the class described, a heater for heating a space, a liquid burner for heating said heater, a space thermostat, means associated with said burner and said thermostat to operate said burner upon the lowering of the space temperature'to a predetermined .value, a liquid storage reservoir associated with said liquid burner for supplying liquid thereto, a warning light associated with said space thermostat, means associated with said liquid storage reservoir to light said warning light upon the existence of a predetermined low liquid level in said reservoir and to stop operation of said liquid burner.

6. In a heating system of the class described, a heater for heating a space, a liquid burner for heating said heater, a space thermostat, means associated with said burner and said thermostat to operate said burner upon the lowering of the space temperature to a predetermined value, a

liquid reservoir associated with said liquid burner for supplying liquid thereto, a warning light associated with said space thermostat, means assomined low liquid level in said reservoir to give a visual indication and to lower the setting of said space thermostat.

'7. In a heating system having a heater for heating a space, a liquid burner and a. liquid reservoir therefor, the combination of a space thermostat for controlling the operation of said liquid burner, liquid level responsive means, and means associated with said space thermostat and operatively connected to said liquid level responsive means and said liquid burner to lower the setting of'said space thermostat upon the establishment of a predetermined low liquid level in said reservoir and upon said space thermostat calling for heat.

8. In a heating system having a heater for heating a space, a liquid burner and a liquid reservoir therefor, the combination of a space thermostat for controlling the operation of said liquid burner, liquid level responsive means, and means associated with said space thermostat and operatively connected to said liquid level responsive means and said liquid burner to lower the setting of said space thermostat when the liquid level in said reservoir reaches a predetermined minimum and the liquid burner is in operation.

9. In a heating system of the class described having a heater for heating a space, a liquid burner and a. liquid reservoir therefor, the combination of a space thermostat for controlling the operation of said liquid burner, a warning I light associated with said space thermostat, and

means responsive to the operation of said liquid burner and the level of the liquid in said reservoir to light said warning light and stop operation of said liquid burner.

10. The combination with a heating system having a heater for heating a space, a liquid burner and a liquid reservoir therefor, of a space thermostat for starting the operation of said liquid burner the lowering of the space temperature to a predetermined value, control means responsive to changes in liquid level in said reservoir, and means associated with said control means and said liquid burner for afi'ecting the operation of said space thermostat upon the establishment of a predetermined low liquid level in said reservoir and upon the starting of said liquid burner'requiring a space tem-,

i1 5 perature lower than said predetermined value to continue operation of 'said liquid burner.

11. In a heating system of the class described,

a heater for heating a space, a liquid burner for heating said heater, a space thermostat, means -'-l0 associated with said burner and said thermo heating said heater, a space thermostat, means.

associated with said burner and said thermostat to operate said burner upon the lowering oi'the space temperature to a predetermined value, a liquid reservoir associated with said liquid burner for supplying liquid thereto, a warning light associated with said space thermostat, means associated with said liquid reservoir and said above mentioned means to light said warning light upon the existence of a predetermined low 7 liquid level in said reservoirand upon operation l of said liquid burner to give a visual indication and to lower the setting of said space thermostat.

13. Ina heating system of the class described,

' a heater for heating a space,. a motor operated 1iquid burner for heating said-heater, a source of power, a spacethermostat, an electric circuit connecting said motor operated liquid burner, "said thermostat and said source of power to operate said burner upon the lowering of the space temperature to a predetermined value, a 5 fuel reservoir, pipingconnections. between said reservoir and said burner whereby liquid fuel is led to said burner, a pressure responsive switching mechanism associated with said piping connections and closed upon the establishment of a predetermined low pressure in the pip-' and said liquid burner is in operation to give a,

visual indication of the liquid level in said res; ervoir. 1 I

14. In a heating system of the class described, a heater for heating a space, a motor operated liquid burner for heating said,heater, a source- 5 of power, a space thermostat, an electric circuit connecting said motor operated liquid burner, ,said thermostat and said source .01 power to operate said burner upon'the lowering oi the tric circuit and connecting said switching mech- Y anism and said warning lamp whereby said warning lamp is lighted when the liquid level'in said reservoir reaches a predetermined low value "and said liquid burner is in operationvto give a visual indication and *to lower the effective setting oi said'space thermostat.

15. In a system oi. the class described, a liquid reservoir, means for controlling the eductlon of liquidirom said reservoir, a control mechanism responsive to a predetermined value oi a condition for controlling said means, a switching mechanism responsive to variations in liquid level in said reservoir, an indicating device asv sociated ,with said control mechanism, means connecting saidswitching mechanism" andsaid indicating device to operate said indicating device upon the establishment of a predetermined low liquid level in said reservoir and to ailect said controlmechanism to make said control mechanism responsive to a diilferent value of the condition. A 1

16. In a device of the character described, a liquid reservoir, a pumping mechanism for pumping liquid from said reservoir, a control mechanism responsiveto a predetermined value of a condition for controlling the operation of said pumping mechanism, a switching mechanism responsive to variations in liquid level in said reservoir, an indicating device associated with said control mechanism, means connecting said switching mechanism .and said indicating device to operate said indicating device upon the establishment of a predetermined low liquid level in said reservoir and to affect said control mechanism to make said control mechanism responsive to a'diflerent value of the condition.

DANIEL a. Tar on. U 

